That is exactly what came to my mind: Dagon.
Well, God is not surprised by this. This is just another way unbelievers fill the cup of His wrath that will be poured out on them.
BTW- wasn’t Dagon referred to as the fish-god because his head looked like a fish head?
Wrong half, I would say.
Other depictions seem to be based on a lot of artistic license and lack of research which seems to produce SWAMP THING.